In R, If I have this data
           date.hour temp
2014-01-05 20:00:00            16
2014-01-06 20:00:00            14
2014-01-06 22:00:00            18
and with seq I can get a sequence of date time
begin <- as.POSIXct('2014-1-5')
end <- as.POSIXct('2014-1-7')
seq(begin, end, by=2*3600)
how I can complete the data to something similar to
           date.hour temp
2014-01-05 00:00:00            NA
2014-01-05 02:00:00            NA
...
2014-01-05 18:00:00            NA
2014-01-05 20:00:00            16
2014-01-05 22:00:00            NA
...
2014-01-06 20:00:00            18
2014-01-06 22:00:00            14
...
2014-01-07 00:00:00            NA
 
     
    